A mammography apparatus is a standard image diagnostic apparatus used in mammary gland image examination. In the mammary gland image examination, mammography images taken by a mammography apparatus are used.
The mammary gland image examination is performed in breast cancer screening, which asymptomatic women are recommended to undergo, for example, once a year or once in several years. An image interpreter examines the mammography images taken by the mammography apparatus to check for microcalcifications, tissue disorders, tumor masses, focal asymmetric densities (FAD), or the like.
The mammary gland image examination is also performed in the follow-up examination for women who have a symptom of breast cancer. The image interpreter examines the mammography images to check for an affected portion or a region of interest (ROI).
In the mammary gland image examination, positioning is important. The positioning has an effect on how to press a breast by a pressing plate of the mammography apparatus, namely, how to spread mammary glands. Thus the mammography images vary depending on the positioning. The variation of the mammography images causes the difference of the positions of the affected portion and ROI between newly-taken mammography image and previously-taken mammography image.
If the positions of the affected portion and ROI are different, the image interpreter has to consider the positioning difference when examining how the mammography images changed with time from previously-taken images. As a result, the efficiency of image interpretation may be lowered.